Error code reference

Samsung Heat Pump Error Code E403

Compressor down by compression ratio control

Compressor down by compression ratio control - ratio of (High pressure + 1)/(Low pressure + 1) exceeds 8.5 for over 10 minutes.

First step from the service manual

Connect S-net and manifold gauge; check if service valve is fully opened; compare S-net with manifold gauge readings.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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Step-by-step tests with expected resistance, voltage, and continuity values
Wiring diagram references and connector pinouts from the OEM service manual
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E403 on my Samsung Heat Pump

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Compressor down by compression ratio control

From Service Manual 323240, p.12:

1.Connect S-net and manifold gauge; check if service valve is fully opened; compare S-net with manifold gauge readings.

2.Measure control board supply voltage at the test points. Expected: 12 VDC and 5 VDC; a drop below 4.75 VDC on the logic rail points to a failed onboard regulator.

3.Inspect all connectors on the main control for corrosion, thermal stress, or backed-out pins. Reseat each connector with the power disconnected.

Part DA92-00384N

Main PCB assembly

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First step from the service manual

Get the full diagnostic procedure for E403.

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